The present invention pertains to the field of inserting machines. More particularly, the present invention pertains to monitoring the motion of sheets through a sheet handling device, such as a mailing or high-speed inserter to provide machine control diagnostics.
A typical sheet or envelope handling device includes various structures, motors and sensors. For example, a typical envelope handling device includes an envelope feeding structure for feeding an envelope or a batch of envelopes in singular fashion in a downstream path of travel to a work station. Typical envelope handling devices employ ejection rollers or ejection belts operating at a constant speed, or at some speed that varies as a function of time, speeds chosen so as to avoid envelope collisions and noise. It is beneficial to control to a fine degree the motion of a sheet or envelope handling device so as to keep noise and undesirable motion of the sheets or envelopes to a minimum.
The prior art uses motion profiles to express, as a function of time, the velocity/speed of an axis of a motor that causes motion of a sheet in a mailing system. A motion profile consists of a series of segments, each segment having a duration and each corresponding to a state of motion of an axis of a motor ultimately responsible for imparting motion to a sheet or envelope.
For example, a motor may have an axis that in rotating pulls a sheet through part of a mailing system at a certain speed, after accelerating at a specified acceleration as a function of time, and concluding with some specified deceleration as a function of time. If the sheet does not slip, then the motion of the sheet can be correlated precisely with the motion of the axis of the motor: the sheet moves through the mailing system with a speed that is exactly equal to the speed of rotation of the part of the axis in contact with the sheet, i.e. usually the surface of a belt driven by the axis. In this case, commands are sometimes sent to a motor to impart motion to a sheet, for a series of time segments, based simply on the assumption that the motion of the axis of the motor causing the motion of the sheet can be equated to the motion of the sheet.
On occasion, however, a sheet in a sheet handling device will slip so that the motion of the axis does not necessarily indicate the motion of a sheet (or envelope). Then the motion of an axis of a motor can be conditioned based on receiving commands from sensors used to detect the presence of the sheet as it moves through the sheet handling device.
Typically, and even in such complex sheet handling machines, the operation of these machines is often categorized as simply working or not working without regard for how well the machine is operating, or more importantly, how close it is to failing. Hence there is a need to determine degraded performance in sheet handling machines and to predict likely failure of such a machine for the purpose of proactively adjusting and/or servicing the machine prior to experiencing machine failure. In the prior art, the diagnosis of sheet handling machine control problems was achieved through a combination of inferred cause and effect complied from the theory of how the sheet handling machine was supposed to operate. This prior art method is both imprecise and burdensome as machine problems were often identified after experience of a malfunction often causing damage to the documents being process in the sheet handling machine.
Therefore, it is an object of the present invention to provide a diagnostic methodology for sheet handling machines to continuously monitor and evaluate the operation of sheet handling machines during their operation and interpret collected data in real time to provide diagnostic information indicating as to how the machine is operating.
Accordingly, the present invention relates to a system for providing diagnostic information relating to the performance of an inserter system based upon data collected from documents conveying within the inserter system.
Preferably, it is the control system of the inserter system that is utilized to provide the diagnostic information. In use, the control system is preferably coupled to a roller arrangement in the inserter system utilized for conveying a document in a linear direction, with the control system being further coupled to first and second sensors located in close proximity to the roller arrangement. Each of the sensors are operable to detect at least the presence of a leading edge of a document conveying in close proximity to each sensor. The control system of the inserter determines the number of encoder counts (e.g., incremental rotational movements of a motor in the roller arrangement) it takes for a leading edge of a document to convey from said first sensor to said second sensor and compares the measured encoder counts to a prescribed number of encoder counts and provides diagnostic information based upon this comparison. In the event the diagnostic information reveals poor performance or possible malfunction is to occur in the inserter system, appropriate warning indicators are then provided to an operator of the inserter system.